Ring on a closed web stent-graft for use in tip capture

ABSTRACT

A stent-graft has a closed web end configuration in which endmost stent crowns do not extend beyond an end or edge of a tubular graft. In order to couple the stent-graft to tip capture fingers or prongs of a delivery system, the stent-graft includes a ring woven between the endmost crowns of an end stent. When end stent is in a compressed delivery configuration, sections of the ring between adjacent endmost crowns form attachment loops that longitudinally extend beyond the end of the tubular graft for engaging the tip capture fingers of a delivery system. When the end stent is in an expanded fully deployed configuration, the attachment loops retract back to the stent so that the ring is a circular band having a diameter substantially equal to the expanded diameter of the stent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. patent application Ser. No.13/457,888, filed Apr. 27, 2012, which is hereby incorporated byreference in its entirety for all purposes.

FIELD OF THE INVENTION

The invention is related in general to implantable prostheses and inparticular to self-expanding stent-grafts.

BACKGROUND OF THE INVENTION

Prostheses for implantation in blood vessels or other similar organs ofthe living body are, in general, well known in the medical art. Forexample, prosthetic endovascular grafts constructed of biocompatiblematerials have been employed to replace or bypass damaged or occludednatural blood vessels. In general, endovascular grafts include a graftanchoring component that operates to hold a tubular graft component of asuitable graft material in its intended position within the bloodvessel. Most commonly, the graft anchoring component is one or moreradially compressible stents that are radially expanded in situ toanchor the tubular graft component to the wall of a blood vessel oranatomical conduit. Thus, endovascular grafts are typically held inplace by mechanical engagement and friction due to the opposition forcesprovided by the radially expanded stents.

Grafting procedures are also known for treating aneurysms. Aneurysmsresult from weak, thinned blood vessel walls that “balloon” or expanddue to aging, disease and/or blood pressure in the vessel. Consequently,aneurysmal vessels have a potential to rupture, causing internalbleeding and potentially life threatening conditions. Grafts are oftenused to isolate aneurysms or other blood vessel abnormalities fromnormal blood pressure, reducing pressure on the weakened vessel wall andreducing the chance of vessel rupture. As such, a tubular endovasculargraft may be placed within the aneurysmal blood vessel to create a newflow path and an artificial flow conduit through the aneurysm, therebyreducing if not nearly eliminating the exertion of blood pressure on theaneurysm.

In general, rather than performing an open surgical procedure to implanta bypass graft that may be traumatic and invasive, endovascular graftswhich may be referred to as stent-grafts are preferably deployed througha less invasive intraluminal delivery procedure. More particularly, alumen or vasculature is accessed percutaneously at a convenient and lesstraumatic entry point, and the stent-graft is routed through thevasculature to the site where the prosthesis is to be deployed.Intraluminal deployment is typically effected using a delivery catheterwith coaxial inner and outer tubes or shafts arranged for relative axialmovement. For example, a self-expanding stent-graft may be compressedand disposed within a distal end of an outer shaft or sheath componentof the delivery catheter distal of a stop fixed to an inner shaft ormember. The delivery catheter is then maneuvered, typically trackedthrough a body lumen until a distal end of the delivery catheter and thestent-graft are positioned at the intended treatment site. The stop onthe inner member is then held stationary while the sheath component ofthe delivery catheter is withdrawn. The stop on the inner memberprevents the stent-graft from being withdrawn with the sheath component.As the sheath component is withdrawn, the stent-graft is released fromthe confines thereof and radially self-expands so that at least aportion of it contacts and substantially conforms to a portion of thesurrounding interior of the lumen, e.g., the blood vessel wall oranatomical conduit.

In recent years, to improve optimal control and alignment duringdeployment and positioning of a stent-graft, various tip capturemechanisms have been incorporated into the delivery system utilized forpercutaneously delivering the prosthesis. Tip capture involvesrestraining a proximal end stent of the stent-graft in conjunction witha main body restraint achieved by other delivery system components, suchas a tubular outer shaft or sheath component. The tip capture mechanismcan be activated at any time during stent-graft deployment to suit anynumber of system characteristics driven by the therapy type, stent-grafttype, or specific anatomical conditions that may prescribe the releasetiming. Typically, the tip capture release is activated after some orall of the main stent-graft body release, and thus provides a means ofrestraining the stent-graft during positioning. Additional restraint ofthe stent-graft is a key characteristic when the operator is attemptingto accurately position the stent relative to an anatomical target.

For example, U.S. Patent Application Publication No. 2006/0276872 toArbefuielle et al. and U.S. Patent Application Publication No.2009/0276207 to Glynn et al., both herein incorporated by reference intheir entirety, describe tip capture mechanisms that restrain a proximalend stent of the stent-graft while the remainder of the stent-graftexpands, then releases the proximal end stent. The proximal end stent isattached to the graft material of the stent-graft so as to have an “openweb” or “free flow” proximal end configuration in which the endmostcrowns thereof extend past or beyond the graft material such that theendmost crowns are exposed or bare, and thus free to interact with a tipcapture mechanism and couple the prosthesis to the delivery system. Theopen web proximal end configuration allows blood flow through theendmost crowns for perfusion during and/or after implantation. FIGS. 1Aand 1B illustrate a delivery system 10 having a tip capture mechanism 12designed to couple or interact with a stent-graft 14 having an open webor free flow proximal end configuration 16. More particularly, endmostcrowns 18 of a proximal end stent 15 engage or extend around retractablefinger or prong-like elements 20 of the tip capture mechanism. When anouter delivery shaft 22 is retracted to allow stent-graft 14 toself-expand, endmost crowns 18 of the proximal end stent 15 remainengaged around tip capture fingers 20, as shown in FIG. 1A. To releaseproximal end stent 15, a shaft 24 coupled to finger or prong-likeelements 20 is refracted and end stent 15 is allowed to self-expand, asshown in FIG. 1B. The Captiva Delivery System manufactured by MedtronicVascular, Inc. of Santa Rosa, Calif. is one example of a delivery systemhaving a tip capture mechanism as described above, which may be utilizedfor delivering endovascular stent-grafts such as the Valiant ThoracicStent-graft manufactured by Medtronic Vascular, Inc. of Santa Rosa,Calif.

Tip capture mechanisms have improved accuracy of deployment ofself-expanding stent-grafts having open web or free flow configurations.However, in some cases a closed web configuration may be required orchosen due to application and/or user preferences. In a closed webconfiguration, the endmost crowns do not extend past or beyond the graftmaterial but rather are covered or lined by graft material. For example,a stent-graft having a closed web configuration may be selected to treatdissections or vessel transections due to the related condition of thevessel tissue. In these cases, the tissue is fragile and may be damagedby exposed stent struts or apices. A closed web stent-graft thuspresents a proximal configuration that is less traumatic to sensitivetissues or disease states. However, stent-grafts having a closed webproximal configuration do not have a bare proximal end stent free tointeract with a tip capture mechanism of a delivery system, and thus maypresent challenges during deployment with varied success of achievingcontrol during delivery without utilizing tip capture. Embodimentshereof relate to a stent-graft having a closed web proximal endconfiguration that may interact with a tip capture mechanism of adelivery system.

BRIEF SUMMARY OF THE INVENTION

Embodiments hereof relate to a prosthesis for implantation within a bodylumen, the prosthesis including a tubular graft of a graft material anda stent coupled to the tubular graft. The stent includes a plurality ofcrowns and a plurality of struts with each crown being formed between apair of opposing struts. The stent has endmost crowns that are adjacentto and distal of a proximal edge of the tubular graft. The endmostcrowns are covered by the graft material of the tubular graft. A ringengages each of the endmost crowns of the stent with sections of thering being defined between adjacent endmost crowns. At least one of thesections of the ring longitudinally extends beyond the proximal edge ofthe tubular graft as an attachment loop of the prosthesis when the stentis in a compressed delivery configuration. When the stent is in anexpanded deployed configuration, the ring is a circular band.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features and advantages of the invention will beapparent from the following description of embodiments hereof asillustrated in the accompanying drawings. The accompanying drawings,which are incorporated herein and form a part of the specification,further serve to explain the principles of the invention and to enable aperson skilled in the pertinent art to make and use the invention. Thedrawings are not to scale.

FIGS. 1A and 1B are side views of a distal end of a delivery systemhaving a tip capture mechanism designed to couple or interact with astent-graft having an open web or free flow proximal end configuration.

FIG. 2 is a side view of a stent-graft prosthesis having a ring that iswoven between adjacent endmost crowns of an end stent of thestent-graft, wherein interior and exterior sections of the ring extendbetween adjacent endmost crowns and alternate between inside and outsidesurfaces of the graft of the stent-graft according to an embodimenthereof.

FIG. 3 is a perspective end view of a portion of the stent-graftprosthesis of FIG. 2.

FIG. 4 is a side view of the end of the stent-graft prosthesis of FIG.2, wherein the stent-graft prosthesis has been cut and laid out flat forillustrative purposes only.

FIGS. 5-8 illustrate a method of deploying the stent-graft prosthesis ofFIG. 2, wherein FIGS. 5-6 illustrate the stent-graft prosthesis in adelivery configuration, FIG. 7 illustrates the stent-graft prosthesis ina partially deployed configuration, and FIG. 8 illustrates thestent-graft prosthesis in a fully deployed configuration.

FIG. 9 is a perspective end view of a portion of a stent-graftprosthesis having a ring that is woven between adjacent endmost crownsof an end stent of the stent-graft, wherein sections of the ring thatextend between adjacent endmost crowns extend along the inside surfaceof the graft of the stent-graft according to another embodiment hereof.

FIG. 9A is a side view of the end of the stent-graft prosthesis of FIG.9, wherein the stent-graft prosthesis has been cut and laid out flat forillustrative purposes only.

FIG. 10 is a side view of a portion of the stent-graft prosthesis ofFIG. 9, wherein the stent-graft prosthesis is in a partially deployedconfiguration and every other section of the ring forms a temporaryattachment loop for coupling to a delivery system.

FIG. 10A is an end view of FIG. 10.

FIG. 11 is a side view of a portion of the stent-graft prosthesis ofFIG. 9, wherein the stent-graft prosthesis is in a partially deployedconfiguration and every section of the ring forms a temporary attachmentloop for coupling to a delivery system.

FIG. 11A is an end view of FIG. 11.

FIG. 12 is a perspective end view of a stent-graft prosthesis having aring that is woven between adjacent endmost crowns of an end stent ofthe stent-graft, wherein sections of the ring that extend betweenadjacent endmost crowns extend along the outside surface of the graft ofthe stent-graft according to another embodiment hereof.

FIG. 12A is a side view of the end of the stent-graft prosthesis of FIG.12, wherein the stent-graft prosthesis has been cut and laid out flatfor illustrative purposes only.

FIG. 13 is a perspective end view of a stent-graft prosthesis having aring that is woven between adjacent endmost crowns of an end stent ofthe stent-graft, wherein interior and exterior sections of the ringextend between adjacent endmost crowns and alternate between inside andoutside surfaces of the graft of the stent-graft, with stitches couplingthe exterior sections of the ring to the graft according to anembodiment hereof.

FIG. 14 is a side view of a stent-graft prosthesis having a ring that iswoven between adjacent endmost crowns of a stent adjacent to an endstent of the stent-graft according to another embodiment hereof.

FIG. 15 is a side view of a stent-graft prosthesis having a ring that iswoven between adjacent endmost crowns of an end stent of thestent-graft, wherein a suture extends from the ring to a stent adjacentto the end stent of the stent-graft according to another embodimenthereof.

FIG. 16 is a side view of a stent-graft prosthesis having a ring that iswoven between adjacent endmost crowns of an end stent of thestent-graft, wherein a second suture ring extends around the struts ofthe end stent and is intertwined with the ring woven between adjacentendmost crowns of the end stent according to another embodiment hereof.

FIG. 17 is a side view of a stent-graft prosthesis having a ring that iswoven between adjacent endmost crowns of an end stent of thestent-graft, wherein a second suture ring extends around a stentadjacent to the end stent and is intertwined with the ring woven betweenadjacent endmost crowns of the end stent according to another embodimenthereof.

FIG. 18 is a perspective end view of a stent-graft prosthesis having aring that is woven between adjacent endmost crowns of an end stent ofthe stent-graft, wherein the ring has a sinusoidal shape-setconfiguration according to an embodiment hereof.

FIG. 19 is a side view of a stent-graft having a stent configurationaccording to another embodiment hereof, wherein a ring is woven betweenadjacent endmost crowns of an end stent of the stent-graft according toan embodiment hereof.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Specific embodiments are now described with reference to the figures,wherein like reference numbers indicate identical or functionallysimilar elements. Unless otherwise indicated, for the delivery systemthe terms “distal” and “proximal” are used in the following descriptionwith respect to a position or direction relative to the treatingclinician. “Distal” and “distally” are positions distant from or in adirection away from the clinician, and “proximal” and “proximally” arepositions near or in a direction toward the clinician. For thestent-graft prosthesis “proximal” is the portion nearer the heart by wayof blood flow path while “distal” is the portion of the stent-graftfurther from the heart by way of blood flow path. In addition, the term“self-expanding” is used in the following description with reference toone or more stent structures of the prostheses hereof and is intended toconvey that the structures are shaped or formed from a material that canbe provided with a mechanical memory to return the structure from acompressed or constricted delivery configuration to an expanded deployedconfiguration. Non-exhaustive exemplary self-expanding materials includestainless steel, a pseudo-elastic metal such as a nickel titanium alloyor nitinol, various polymers, or a so-called super alloy, which may havea base metal of nickel, cobalt, chromium, or other metal. Mechanicalmemory may be imparted to a wire or stent structure by thermal treatmentto achieve a spring temper in stainless steel, for example, or to set ashape memory in a susceptible metal alloy, such as nitinol. Variouspolymers that can be made to have shape memory characteristics may alsobe suitable for use in embodiments hereof to include polymers such aspolynorborene, trans-polyisoprene, styrene-butadiene, and polyurethane.As well poly L-D lactic copolymer, oligo caprylactone copolymer and polycyclo-octine can be used separately or in conjunction with other shapememory polymers.

The following detailed description is merely exemplary in nature and isnot intended to limit the invention or the application and uses of theinvention. Although the description of the invention is in the contextof treatment of blood vessels such as the coronary, carotid and renalarteries, the invention may also be used in any other body passagewayswhere it is deemed useful. Furthermore, there is no intention to bebound by any expressed or implied theory presented in the precedingtechnical field, background, brief summary or the following detaileddescription.

Embodiments hereof relate to a stent-graft prosthesis having a closedweb end configuration, and more particularly relate to an apparatus andmethod for securing a stent-graft prosthesis having a closed web endconfiguration to tip capture fingers or prongs of a delivery system. Aswill be explained in more detail below, the stent-graft prosthesisincludes a strand of material that is woven between adjacent endmostcrowns of the stent-graft to form a ring with sections of the ring beingdefined between adjacent endmost crowns. One or more section(s) of thering transform or transition into attachment loops for coupling orhitching to tip capture fingers or prongs of a delivery system.Additional description and features are described below with referenceto the figures.

Referring to FIG. 2-3, stent-graft prosthesis 200 includes a tubulargraft 205 having a longitudinal axis L_(A), first edge or end 202, asecond edge or end 204, and a body 203 there between which defines alumen 301 through stent-graft prosthesis 200. In an embodiment, firstedge 202 of tubular graft 205 may be referred to as a proximal end oredge of tubular graft 205 and a proximal end or edge of stent-graftprosthesis 200, which is conventionally the end that is coupled to a tipcapture mechanism of a delivery system, and second edge 204 of tubulargraft 205 may be referred to as a distal end or edge of graft 204 and adistal end or edge of stent-graft prosthesis 200. Tubular graft 205 maybe formed from any suitable graft material, for example and not limitedto, a low-porosity woven or knit polyester, DACRON material, expandedpolytetrafluoroethylene, polyurethane, silicone, or other suitablematerials. In another embodiment, the graft material could also be anatural material such as pericardium or another membranous tissue suchas intestinal submucosa.

Stent-graft prosthesis 200 also includes at least oneradially-compressible stent or scaffold 206 that is coupled to tubulargraft 205 for supporting the graft material and is operable toself-expand into apposition with an interior wall of a body vessel (notshown). In the embodiment depicted in FIG. 2, stent-graft prosthesis 200is shown in its fully expanded or deployed configuration and includes aseries of six independent or separate cylindrical stents 206. Each stent206 is constructed from a self-expanding or spring material, such asNitinol, and is a sinusoidal patterned ring including a plurality ofcrowns or bends 208 and a plurality of struts or straight segments 209with each crown being formed between a pair of opposing struts. Althoughshown with six stents, it will be understood by one of ordinary skill inthe art that stent-graft prosthesis 200 may include a greater or smallernumber of stents depending upon the desired length of stent-graftprosthesis 200 and/or the intended application thereof. For descriptionpurposes only, the stent that is coupled adjacent and proximate to firstedge 202 of tubular graft 205 is referred to herein as first or proximalend stent 206A and the stent that is coupled adjacent and proximate tosecond edge 204 of tubular graft 205 is referred to herein as second ordistal end stent 206B. Proximal end stent 206A is coupled to tubulargraft 205 distal to first or proximal edge 202 of tubular graft 205.Stents 206 are shown in FIG. 2 has having identical sinusoidal patternsbut it will be understood by one of ordinary skill in the art that oneor more of stents 206 may have a different pattern or configuration.Stents 206 are coupled to tubular graft 205 by stitches or other meansknown to those of skill in the art. In the embodiment shown in FIG. 2,stents 206 are coupled to an outside surface of tubular graft 205.However, stents 206 may alternatively be coupled to an inside surface oftubular graft 205. When stent-graft prosthesis 200 is used for treatingan aneurysm, stents 206 have sufficient radial spring force andflexibility to conformingly engage stent-graft prosthesis 200 with thebody lumen inner wall, to avoid excessive leakage, and preventpressurization of the aneurysm, i.e., to provide a leak-resistant seal.Although some leakage of blood or other body fluid may occur into theaneurysm isolated by stent-graft prosthesis 200, an optimal seal willreduce the chances of aneurysm pressurization and resulting rupture.

At least first edge 202 of stent-graft prosthesis 200 has a closed webconfiguration in which endmost crowns 208A of first end stent 206A arecovered or lined by tubular graft 205 and do not extend past or beyondfirst edge 202 of tubular graft 205. As utilized herein, “endmost”crowns are the crowns or peaks of a stent that are most proximate to andinwardly spaced apart from an end or edge of tubular graft 205, such asfirst edge 202. In the embodiment of FIG. 2, end stent 206A is coupledto the graft material so as to have a first set of endmost crowns 208Aadjacent to and distal of first or proximal edge 202 of tubular graft205 and a second or opposing set of crowns 211 distant from first orproximal edge 202 of tubular graft 205 relative to the first set ofendmost crowns. Endmost crowns 208A of end stent 206A may be stitched orotherwise secured to tubular graft 205. In the embodiment depicted inFIG. 2, endmost crowns 208B of distal end stent 206B are also covered orlined by tubular graft 205, i.e, do not extend outside of or beyondsecond edge 204 of tubular graft 205, and are stitched or otherwisesecured to tubular graft 205. In another embodiment hereof (not shown),endmost crowns 208B of second edge stent 206B may extend beyond secondedge 204 of tubular graft 205 in an open web or free-flow configuration.

Rather than utilizing endmost crowns 208A of first end stent 206A tocouple the prosthesis to a delivery system as in open-web or free-flowconfigurations, prosthesis 200 includes a ring 207 to couple theprosthesis to a delivery system during initial deployment. Ring 207 is astrand 213 of material that forms a continuous hoop or circular bandhaving a diameter substantially equal to the expanded diameter of endstent 206A. As utilized herein, “substantially equal to” the expandeddiameter of an end stent includes a ring or circular band having adiameter equal to the expanded diameter of the end stent with a 5%margin of error. In an embodiment, the expanded outer diameter of endstent 206A, as well as the diameter of ring 207, may be intentionallyoversized with respect to the target vessel and be between 5% and 20%greater than the diameter of the target inner vessel wall. For example,stent-graft prosthesis 200 may have a 40 mm expanded diameter for atarget vessel ranging from 38 mm, in the case of a dissection ortransection, to 32 mm, in the case of an aneurysm. Thus, when implantedwithin the target vessel and thus restricted to the smaller lumenaldiameter thereof, an over-sized ring 207 may not extend to its fulldiameter and excess material of ring 207 may reside on the inside oroutside of the stent-graft.

Ring 207 engages or extends through each endmost crown 208A of end stent206A. As best shown in FIGS. 3 and 4, a first end 217 of strand 213pierces and is threaded through the graft material of tubular graft 205within each endmost crowns 208A of first end stent 206A until the strandis woven between adjacent endmost crowns 208A of first end stent 106Aand extends around the circumference of end stent 206A. Once strand 213extends around the circumference of end stent 206A, first end 217 ofstrand 213 is then coupled or attached to a second end 219 of strand 213to form ring 207. Each endmost crown 208A of end stent 206A is ensnaredor captured by ring 207. Ring 207 includes a plurality of integralsections which each extend between adjacent endmost crowns 208A andcollectively encircle endmost crowns 208A of stent 206A as a circularband. In the embodiment of FIG. 2, sections of ring 207 extendingbetween adjacent endmost crowns 208A alternate between inside andoutside surfaces of tubular graft 205. More particularly, interiorsections or portions 230 of ring 207 extends between adjacent endmostcrowns 208A along an inside surface of tubular graft 205, and exteriorsections or portions 232 of ring 207 extend between adjacent endmostcrowns 208A along an outside surface of tubular graft 205. Besides beingwoven between endmost crowns 208A of first end stent 206A, ring 207 isnot stitched or otherwise attached to prosthesis 200 and is thereforeallowed to slide through or freely rotate between the stent crowns.

Referring now to FIGS. 5-8, ring 207 is utilized for coupling first edge202 of prosthesis 200 to a retractable tip capture spindle 512 of adelivery system 510. Delivery system 510 includes at least an outerdelivery sheath 522 and a catheter shaft 524 having tip capture spindle512 mounted thereon. Prosthesis 200 is also mounted on catheter shaft524 and outer delivery sheath 522 covers and restrains prosthesis 200 ina compressed configuration for delivery thereof. In an embodiment,delivery system 510 is the Captiva Delivery System, manufactured byMedtronic Vascular, Inc. of Santa Rosa, Calif., or is a delivery systemas described in U.S. Patent Application Publication No. 2009/0276207 toGlynn et al., previously incorporated by reference in its entirety. Onlya distal end of delivery system 510 is shown in the figures. FIGS. 5 and6 illustrate prosthesis 200 in a delivery configuration, in whichprosthesis 200 is mounted on catheter shaft 524 with outer deliverysheath 522 covering and restraining prosthesis 200 in a compressedconfiguration for delivery thereof. Interior sections 230 of ring 207transform or transition into temporary attachment loops 540 thatlongitudinally extend, i.e., extend in the direction of longitudinalaxis L_(A) of tubular graft 205 shown in FIG. 2, beyond first orproximal edge 202 of prosthesis 200 and engage or extend around prong orfinger-like elements 520 of tip capture spindle 512. In anotherembodiment (not shown), exterior sections 232 of ring 207 mayalternatively transform or transition into temporary attachment loops540. FIG. 6 illustrates prosthesis 200 in a delivery configuration withouter delivery sheath 522 slightly trimmed or cut back to expose tipcapture fingers 520 for illustrative purposes.

When initial or partial deployment of prosthesis 200 is desired, outerdelivery sheath 522 is retracted to allow body 203 of prosthesis 200 toself-expand. As shown in FIG. 7, when stent-graft prosthesis 200 is in apartially deployed configuration, interior sections 230 of ring 207remain engaged with tip capture fingers 520 and first end stent 206A isallowed to partially open or deploy, thereby allowing blood flow throughstent-graft prosthesis 200. Notably, prosthesis 200 is still coupled todelivery system 510 via ring 207 to permit repositioning if required.

After any and all repositioning is performed and prosthesis 200 ispositioned as desired, prosthesis 200 may be finally deployed andreleased from delivery system 510 by retracting catheter shaft 524 andthereby retracting tip capture spindle 512. Tip capture fingers 520 areretracted and are disengaged from interior sections 230 of ring 207.When ring 207 is no longer coupled to delivery system 510, first endstent 206A is permitted to fully expand or deploy as shown in FIG. 8. Asfirst end stent 206A expands, temporary attachment loops 540 are pulledback or retract towards stent 206A such that interior sections 230 ofring 207 resume extending along an inside surface of graft 205 asdescribed with respect to FIGS. 2-4, and ring 207 is a circular bandthat encircles endmost crowns 208A of end stent 206A. When first endstent 206A reaches its fully deployed expanded diameter, ring 207 iscompletely pulled back into end stent 206A and no sections of ring 207extend beyond the first or proximal edge 202 of tubular graft 205. Thefully deployed or expanded configuration of prosthesis 200 is thus aclosed web configuration in which neither endmost crowns 208A of firstend stent 206A nor ring 207 extend past first or proximal edge 202 ofprosthesis 200. When deployed in situ, ring 207 has substantially thesame diameter as expanded end stent 206A and is therefore taut ortightly stretched between endmost crowns 208A of end stent 206A. In anembodiment, interior sections 230 of ring 207 restrain or hold openflaps 842 of graft material extending between endmost crowns 208A offirst end stent 206A. The tautness of ring 207 between endmost crowns208A of end stent 206A allows interior sections 230 to impart enoughforce on flaps 842 to keep the flaps open and pressed against the vesselwall.

In coupling prosthesis 200 to delivery system 510, ring 207 provides theadvantages of a free-flow or open web proximal end configuration toprosthesis 200 during initial or partial deployment while retaining theclosed web configuration of prosthesis 200 after full or finaldeployment. More particularly, as described above with respect to FIG.7, the partially deployed configuration of first end stent 206A allowsblood flow there through while prosthesis 200 is still coupled todelivery system 510 via ring 207 for repositioning if required. Sinceblood flow is allowed through partially deployed prosthesis 200, ring207 reduces the issue of blood flow impacting the outer surface ofprosthesis 200 during initial or partial deployment, otherwise known asthe “watermelon seed” effect in which blood flow against an outersurface of the prosthesis may unintentionally force the prosthesisdownstream during final deployment thereof. If closed-web endmost crownsof an end stent were coupled to a tip capture mechanism without ring207, the graft extends all the way to the delivery system and providesan increased surface area that the blood flows acts on, therebyincreasing the watermelon seed effect. However, ring 207 prevents suchincreased surface area because it allows blood to flow throughattachment loops 540 of the partially deployed prosthesis 200 similar toprostheses having open-web or free-flow proximal end configurations.However, unlike prostheses having free-flow or open web proximal endconfigurations, attachment loops 540 formed by ring 207 retract backwithin tubular graft 205 after release from the delivery system so thatprosthesis 200 has a closed-web proximal end configuration after finaldeployment.

In addition, ring 207 allows a greater length or amount of body 203 ofprosthesis 200 to expand into apposition with the vessel wall duringinitial or partial deployment as compared to a configuration which usesan end stent of a stent-graft to couple the stent-graft to a deliverysystem. More particularly, as described above with respect to FIG. 7,when partially deployed the interior sections 230 of ring 207 transitioninto attachment loops 540 that extend beyond first edge 202 ofprosthesis 200 and engage or extend around prong or finger-like elements520 of tip capture spindle 512. As such, attachment loops 540 separateor distance tubular graft 205 from delivery system 510. As compared tostent-grafts having open-web or free-flow proximal end configurationsthat engage the delivery system, attachment loops 540 increase thedistance between first end stent 206A and the delivery system tipcapture spindle 512 and a greater length of prosthesis is allowed todeploy or expand into apposition with the vessel wall while ring 207 isstill coupled to delivery system 510, i.e., pre-tip release. Theincreased amount of apposition helps to prevent the watermelon seedeffect.

As compared to stents 206, ring 207 is not expanding or openingprosthesis 200 and thus is not required to be formed of a springmaterial having sufficient force to deploy prosthesis 200. Ring 207 maybe formed from Nitinol (NiTi), a nickel-titanium alloy, or varioussuture compositions. If formed from Nitinol (NiTi) or another materialthat may be shape set, ring 207 may be shape set as a circular band thathas a diameter substantially equal to the diameter of expanded stent206A. Shape setting ring 207 is not required, but helps to ensure thatattachment loops 540 of ring 207 completely recoil or retract intotubular graft 205 upon full deployment of prosthesis 200.

Referring now to FIGS. 9-9A, another embodiment hereof is shown in whicha ring 907 for coupling a stent-graft prosthesis 900 to a deliverysystem is woven completely along the inside surface of the graftmaterial of a tubular graft 905. Stent-graft prosthesis 900 is similarto stent-graft prosthesis 200 and includes a tubular graft 905 of graftmaterial which defines a lumen 901. Stent-graft prosthesis 900 is in itsfully expanded or deployed configuration but only a first edge 902 oftubular graft 905 is shown in FIG. 9. First or proximal end 902 ofstent-graft prosthesis 900 has a closed web configuration in whichendmost crowns 908A of a first end stent 906A are covered or lined bytubular graft 905 and do not extend past or beyond first edge 902 oftubular graft 905. First end stent 906A is coupled to an inside surfaceof tubular graft 905. As described with respect to ring 207, a strand ofmaterial is woven around end stent 906A and the ends of the strand arethen coupled together to form ring 907 that engages or extends throughendmost crowns 908A of first end stent 906A. In this embodiment,however, ring 907 does not pierce or pass through the graft material oftubular graft 905, resulting in a plurality of interior sections orportions 930 that extend between adjacent endmost crowns 908A along aninside surface of tubular graft 905. Besides being woven between endmostcrowns 908A of first end stent 906A, ring 907 is not stitched orotherwise attached to prosthesis 900 and is therefore allowed to slidethrough or freely rotate between the stent crowns. Since interiorsections 930 each extend along the inside surface of tubular graft 905,ring 907 restrains or holds open each flap of graft material extendingbetween endmost crowns 908A of first end stent 906A after fulldeployment, as described above with respect to FIG. 8.

As shown in FIG. 10, alternating sections of ring 907, i.e., every othersection 930, may transform into attachment loops 1040 that extend beyondfirst edge 902 of prosthesis 900 to engage or extend around prongs orfingers of a tip capture mechanism on a delivery system (not shown). Inthis configuration, the number of attachment loops 1040 that couple tothe delivery system is equal to half of the total number of endmoststent crowns. For example, if first end stent 906A includes six endmoststent crowns 908A, three alternating sections 930 of ring 907 form threeattachment loops 1040 that engage or extend around fingers of the tipcapture mechanism of the delivery system. In another embodiment shown inFIG. 11, all sections 930 of ring 907 may transform into attachmentloops 1140 that extend beyond first edge 902 of prosthesis 900 to engageor extend around prongs or fingers of a tip capture mechanism on adelivery system (not shown). In this configuration, the number ofattachment loops 1140 that couple to the delivery system is equal to thetotal number of endmost stent crowns. For example, if first end stent906A includes six endmost stent crowns 908A, the six sections 930 ofring 907 form six attachment loops 1140 that engage or extend aroundfingers of the tip capture mechanism of the delivery system. Whencoupled to a delivery system, first end stent 906A is separated from thetip capture mechanism of the delivery system by attachment loops 1140.Thus, the distance between end stent 906A and the delivery system isequal to the length of attachment loops 1140. The length of each section930 is approximately equal to the circumference of tubular graft 905divided by the number of crowns of end stent 906A. When each section 930forms a loop 1140, the length of each loop 1140 is approximately thelength of each section divided by two. For example, if tubular graft 905has a 40 mm diameter and first end stent 906A has six endmost crowns908A, the length of each section 930 is approximately equal to (pi*40)/6or approximately 21 mm and the length of each loop 1140 is approximatelyequal to 10.5 mm.

The desired number of attachment loops utilized for coupling theprosthesis to the delivery system may depend upon various factors,including but not limited to the number of prongs or fingers of the tipcapture mechanism, the desired crossing profile of the delivery system,and the desired diameter of first edge 902 during partial deployment.More particularly, as can be seen from a comparison of the end views ofFIG. 10A and FIG. 11A, stent-graft 900 has a smaller end opening when agreater number of attachment loops are utilized for coupling theprosthesis to the delivery system. When alternating sections of ring 907form three attachment loops 1040 for coupling to the delivery system asshown in FIGS. 10, 10A, the end opening has a diameter D₁ which isgreater than diameter D₂, the diameter of the end opening of FIGS. 11,11A in which all sections of ring 907 form attachment loops 1140 forcoupling to the delivery system. The difference in the end openingdiameters is due to the fact that attachment loops 1040 are longer thanattachment loops 1140 because the circumference of ring 907 is spread ordivided between only three attachment loops 1040 rather than sixattachment loops 1140. As can be seen in FIG. 10 and previouslydescribed FIG. 7 in which the stent-grafts are in partially deployedconfigurations, when the attachment loops are longitudinally extendedbeyond the end of the graft, adjacent crowns of the ring sections thatdo not form attachment loops are pulled together and the length ofattachment loops is increased/maximized. A relatively smaller endopening such as the one shown in FIG. 11A provides the operator withmore control if repositioning of the prosthesis is required. However,using alternating sections to the ring to form attachment loops thatcouple to the delivery system as shown in FIG. 7 and FIG. 10 allow theattachment loops to be longer than if every section of the ring is used,thereby separating the first end stent 906A and the delivery system tipcapture mechanism by a greater distance. By increasing the distancebetween the first end stent 906A and the delivery system tip capturemechanism, a greater length of prosthesis is allowed to deploy or expandinto apposition with the vessel wall pre-tip release to prevent theso-called watermelon seed effect as described above.

FIGS. 12-12A illustrate another embodiment hereof in which a ring 1207for coupling a stent-graft prosthesis 1200 to a delivery system is wovencompletely along the outside surface of the graft material of a tubulargraft 1205. Stent-graft prosthesis 1200 is similar to stent-graftprosthesis 200 and includes a tubular graft 1205 of graft material whichdefines a lumen 1201. Stent-graft prosthesis 1200 is in its fullyexpanded or deployed configuration but only a first edge 1202 of tubulargraft 1205 is shown in FIG. 12. First edge 1202 of stent-graftprosthesis 1200 has a closed web configuration in which endmost crowns1208A of a first end stent 1206A are covered or lined by tubular graft1205 and do not extend past or beyond first edge 1202 of tubular graft1205. First end stent 1206A is coupled to an outside surface of tubulargraft 1205. As described with respect to ring 207, a strand of materialis woven around end stent 1206A and the ends of the strand are thencoupled together to form ring 1207 that engages or extends throughendmost crowns 1208A of first end stent 1206A. In this embodiment,however, ring 1207 does not pierce or pass through the graft material oftubular graft 1205, resulting in a plurality of exterior sections orportions 1232 that extend between adjacent endmost crowns 1208A along anoutside surface of tubular graft 1205. Besides being woven betweenendmost crowns 1208A of first end stent 1206A, ring 1207 is not stitchedor otherwise attached to prosthesis 1200 and is therefore allowed toslide through or freely rotate between the stent crowns. One or moresections 1232 of ring 1207 are utilized for forming attachment loops(not shown) that extend beyond first edge 1202 of prosthesis 1200 tocouple the prosthesis to a delivery system (not shown). For example, asexplained above with respect to FIGS. 10-11, alternating sections ofring 1207 or all sections of ring 1207 may transform into attachmentloops for coupling to the delivery system.

Regardless of the number of attachment loops utilized for coupling theprosthesis to the delivery system, it is essential in all embodimentshereof that the longitudinally-extending attachment loops used to holdthe end stent to the delivery system in a delivery configuration retractor retreat back towards the prosthesis such that the ring returns to orresumes its circular shape that lies against the tubular graft distal ofa proximal edge of the prosthesis when the end stent is in a fullydeployed configuration. As explained above with respect to FIG. 8, thetemporary attachment loops are pulled back towards the prosthesis whenthe end stent is released from the delivery system and self-expands.Thus, the inherent spring forces of the stent ensure that the attachmentloops are pulled back so that the ring retracts completely distal of aproximal edge of the tubular graft and encircles the endmost crowns ofthe end stent. FIGS. 13-18 relate to various features and/or mechanismsto further ensure complete retraction of the attachment loops to the endstent. The features and/or mechanisms to further ensure completeretraction of the attachment loops may be utilized alone or in anycombination. Beginning with an embodiment shown in FIG. 13, one or moresections of the ring may be coupled to the graft material of the graftto assist in retraction of the attachment loops. More particularly,stent-graft prosthesis 1300 is similar to stent-graft prosthesis 200 andincludes a tubular graft 1305 of graft material which defines a lumen1301. Stent-graft prosthesis 1300 is in its fully expanded or deployedconfiguration but only a first proximal end 1302 of tubular graft 1305is shown in FIG. 13, which has a closed web configuration in whichendmost crowns 1308A of a first end stent 1306A are covered or lined bytubular graft 1305 and do not extend past or beyond first edge 1302 oftubular graft 1305. First end stent 1306A is coupled to an outsidesurface of tubular graft 1305, but may alternatively be coupled to aninside surface thereof. As described with respect to ring 207, a strandof material is woven around end stent 1306A and the ends of the strandare then coupled together to form ring 1307 that engages or extendsthrough endmost crowns 1308A of first end stent 1306A. Ring 1307 issimilar to ring 207 in that it passes through the graft material oftubular graft 1305 within each endmost crown 1308A of first end stent1306A such that ring 1307 includes alternating interior and exteriorsections 1330, 1332, respectively, which extend along inside and outsidesurfaces of tubular graft 1305, respectively. When coupled to a deliverysystem (not shown), interior sections 1330 that extend along the insidesurface of tubular graft 1305 are utilized to transform into attachmentloops (not shown) that extend beyond first edge 1302 of prosthesis 1300.One or more stitches 1344 couple or attach exterior sections 1332 ofring 1307 to the graft material of tubular graft 1305. Securing exteriorsections 1332 of ring 1307 to tubular graft 1305 assists in retractionof the attachment loops when the prosthesis is fully deployed, becausestitches 1344 function as anchors that assist in pulling the attachmentloops back towards tubular graft 1305 after stent-graft prosthesis 1300is fully deployed. Although stitches 1344 are shown with a ring that hasalternating interior and exterior sections, it will be understood by oneof ordinary skill in the art that the stitches may be utilized in anyembodiment described herein, including those in which the ring does notpierce the graft material but rather extends solely along the inside oroutside surface of the graft material.

Another embodiment to further ensure complete retraction of theattachment loops to the end stent is shown in FIG. 14 in which the ringis coupled to the stent adjacent to the first end stent. Stent-graftprosthesis 1400 is similar to stent-graft prosthesis 200 and includes atubular graft 1405 having a first proximal edge or end 1402, a seconddistal edge or end 1404, and a body 1403 there between which defines alumen (not shown) through stent-graft prosthesis 1400. Stent-graftprosthesis 1400 is shown in its fully expanded or deployedconfiguration. Rather than being coupled to the first end stent as shownin FIG. 2, a ring 1407 is coupled to a second stent 1406C, which is nextin order to and distal of first end stent 1406A. Ring 1407 is similar toring 207 in that it passes through the graft material of tubular graft1405 within each endmost crown 1408C of second stent 1406C such thatring 1407 includes alternating interior and exterior sections 1430,1432, respectively, which extend along inside and outside surfaces oftubular graft 1405, respectively. Coupling ring 1407 to stent 1406Crather than first end stent 1406A assists in retraction of theattachment loops when the prosthesis is fully deployed, because thespring or deployment force of both stent 1406C and first stent 1406Apull the attachment loops back towards the interior surface of thetubular graft 1405 after stent-graft prosthesis 1400 is fully deployed.Although ring 1407 is shown with alternating interior and exteriorsections, it will be understood by one of ordinary skill in the art thatthe ring may be coupled to stent 1406C via any configuration describedherein, including those in which the ring does not pierce the graftmaterial but rather extends solely along the inside or outside surfaceof the graft material.

Another embodiment to further ensure complete retraction of theattachment loops is shown in FIG. 15 in which one or more sections ofthe ring are coupled to the stent adjacent to the first end stent.Stent-graft prosthesis 1500 is similar to stent-graft prosthesis 200 andincludes a tubular graft 1505 having a first proximal edge or end 1502,a second distal edge or end 1504, and a body 1503 there between whichdefines a lumen (not shown) through stent-graft prosthesis 1500.Stent-graft prosthesis 1500 is shown in its fully expanded or deployedconfiguration. As described with respect to ring 207, a strand ofmaterial is woven around of end stent 1506A and the ends of the strandare then coupled together to form ring 1507 that engages or extendsthrough endmost crowns 1508A of first end stent 1506A. Ring 1507 issimilar to ring 207 in that it passes through the graft material oftubular graft 1505 within each endmost crown 1508A of first end stent1506A such that ring 1507 includes alternating interior and exteriorsections 1530, 1532, respectively, which extend along inside and outsidesurfaces of tubular graft 1505, respectively. When coupled to a deliverysystem (not shown), interior sections 1530 that extend along the insidesurface of tubular graft 1505 are utilized to form attachment loops (notshown) that extend beyond first edge 1502 of prosthesis 1500. A sutureor stitch 1546 couples or attaches an exterior section 1532 of ring 1507to a stent 1506C, which is adjacent to and distal of first end stent1506A. Securing one or more exterior sections 1532 of ring 1507 to stent1506C assists in refraction of the attachment loops when the prosthesisis fully deployed, because suture 1546 functions as an anchor thatassists in pulling the attachment loops back towards tubular graft 1505.Although suture 1546 is shown with a ring that has alternating interiorand exterior sections, it will be understood by one of ordinary skill inthe art that the suture may be utilized in any embodiment describedherein, including those in which the ring does not pierce the graftmaterial but rather extends solely along the inside or outside surfaceof the graft material.

Additional embodiments to further ensure complete retraction of theattachment loops are shown in FIG. 16 and FIG. 17, in which a secondsuture ring functions as an anchor that assists in pulling theattachment loops back towards the graft. In FIG. 16, the second suturering encircles the first end stent around the struts of the stent, andin FIG. 17, the second suture ring encircles a second stent adjacent toand distal of the first end stent. Referring first to FIG. 16,stent-graft prosthesis 1600 is similar to stent-graft prosthesis 200 andincludes a tubular graft 1605 having a first proximal edge or end 1602,a second distal edge or end 1604, and a body 1603 there between whichdefines a lumen (not shown) through stent-graft prosthesis 1600.Stent-graft prosthesis 1600 is shown in its fully expanded or deployedconfiguration. As described with respect to ring 207, a strand ofmaterial is woven around end stent 1606A and the ends of the strand arethen coupled together to form ring 1607 that engages or extends throughendmost crowns 1608A of first end stent 1606A. Ring 1607 is similar toring 207 in that it passes through the graft material of tubular graft1605 within each endmost crown 1608A of first end stent 1606A such thatring 1607 includes alternating interior and exterior sections 1630,1632, respectively, which extend along inside and outside surfaces oftubular graft 1605, respectively. When coupled to a delivery system (notshown), interior sections 1630 that extend along the inside surface oftubular graft 1605 are utilized to form attachment loops (not shown)that extend beyond first edge 1602 of prosthesis 1600. Ring 1607 has adiameter substantially equal to the expanded diameter of first end stent1606A. A second suture ring 1650 is coupled to and encircles first endstent 1606A, around struts 1609 of first end stent 1606A. Second suturering 1650 may be woven between adjacent struts 1609 and/or coupled tostruts 1609 via stitching. In an alternative embodiment (not shown),second suture ring 1650 may encircle first end stent 1606A around asecond or opposing set of crowns 1611. Second suture ring 1650 hooks orloops around ring 1607 at least one intersection point on at least oneexterior section 1632 so that it may act as an anchor that assists inpulling the attachment loops back towards the interior surface of thetubular graft 1605. Although second suture ring 1650 is shown as loopingaround only one exterior section 1632 in FIG. 16, it will be understoodby one of ordinary skill in the art that second suture ring 1650 mayloop around any section of ring 1607 that is not utilized to formattachment loops that extend beyond the first edge of the prosthesisduring delivery. The length of second suture ring 1650 is longer thanthe length of the strand utilized for form ring 1607 because secondsuture ring 1650 is extends around the circumference of stent-graftprosthesis 1600 and also extends longitudinally to interface with ring1607. The length of second suture ring 1650 varies depending upon howmany sections of ring 1607 it loops around. In another embodiment (notshown), ring 1607 may have a diameter greater than the expanded diameterof first end stent 1606A to facilitate the interface or intersectionwith second suture ring 1650. Although attachment ring 1607 is shownwith alternating interior and exterior sections, it will be understoodby one of ordinary skill in the art that second suture ring 1650 may beutilized in any embodiment described herein, including those in whichthe attachment ring does not pierce the graft material but ratherextends solely along the inside or outside surface of the graftmaterial.

The embodiment of FIG. 17 is similar to that of FIG. 16 except that thesecond suture ring is coupled to a second stent adjacent to and distalof the first end stent. More particularly, stent-graft prosthesis 1700includes a tubular graft 1705 having a first proximal edge or end 1702,a second distal edge or end 1704, and a body 1703 there between whichdefines a lumen (not shown) through stent-graft prosthesis 1700.Stent-graft prosthesis 1700 is shown in its fully expanded or deployedconfiguration. As described with respect to ring 207, a strand ofmaterial is woven around end stent 1706A and the ends of the strand arethen coupled together to form ring 1707 that engages or extends throughendmost crowns 1708A of first end stent 1706A. Ring 1707 is similar toring 207 in that it passes through the graft material of tubular graft1705 within each endmost crown 1708A of first end stent 1706A such thatring 1707 includes alternating interior and exterior sections 1730,1732, respectively, which extend along inside and outside surfaces oftubular graft 1705, respectively. When coupled to a delivery system (notshown), interior sections 1730 that extend along the inside surface oftubular graft 1705 are utilized to form attachment loops (not shown)that extend beyond first edge 1702 of prosthesis 1700. Ring 1707 has adiameter substantially equal to the expanded diameter of first end stent1706A. A second suture ring 1750 is woven between endmost crowns 1708Cof a stent 1706C, which is next in order to and distal of first endstent 1606A. Second suture ring 1750 may be woven between adjacentendmost crowns 1708C and/or coupled to stent 1706C via stitching. Secondsuture ring 1750 wraps or loops around ring 1707 at least oneintersection point on at least one exterior section 1732 so that it mayact as an anchor that assists in pulling the loops back towards theinterior surface of the tubular graft 1705. Although second suture ring1750 is shown as looping around only one exterior section 1732 in FIG.17, it will be understood by one of ordinary skill in the art thatsecond suture ring 1750 may loop around any section of ring 1707 that isnot utilized to form attachment loops that extend beyond the first edgeof the prosthesis during delivery. The length of second suture ring 1750is longer than the length of the strand utilized for form ring 1707because second suture ring 1750 is extends around the circumference ofstent-graft prosthesis 1700 and also extends longitudinally to interfacewith ring 1707. The length of second suture ring 1750 varies dependingupon how many sections of ring 1707 it loops around. In anotherembodiment (not shown), ring 1707 may have a diameter greater than theexpanded diameter of first end stent 1706A to facilitate the interfaceor intersection with second suture ring 1750. Although attachment ring1707 is shown with alternating interior and exterior sections, it willbe understood by one of ordinary skill in the art that second suturering 1750 may be utilized in any embodiment described herein, includingthose in which the attachment ring does not pierce the graft materialbut rather extends solely along the inside or outside surface of thegraft material.

Another embodiment to further ensure complete retraction of theattachment loops is shown in FIG. 18 in which the ring has a sinusoidalshape-set configuration. Stent-graft prosthesis 1800 is similar tostent-graft prosthesis 200 and includes a tubular graft 1805 of graftmaterial which defines a lumen 1801. Stent-graft prosthesis 1800 is inits fully expanded or deployed configuration but only a first proximalend 1802 of tubular graft 1805 is shown in FIG. 18. First edge 1802 ofstent-graft prosthesis 1800 has a closed web configuration in whichendmost crowns 1808A of a first end stent 1806A are covered or lined bytubular graft 1805 and do not extend past or beyond first edge 1802 oftubular graft 1805. Ring 1807 is similar to ring 207 in that it passesthrough the graft material of tubular graft 1805 within each endmostcrown 1808A of first end stent 1806A such that ring 1807 includesalternating interior and exterior sections 1830, 1832, respectively,which extend along inside and outside surfaces of tubular graft 1805,respectively. When coupled to a delivery system (not shown), interiorsections 1830 that extend along the inside surface of tubular graft 1805are utilized to form attachment loops (not shown) that extend beyondfirst edge 1802 of prosthesis 1800. In order to assist in retraction ofthe attachment loops when the prosthesis is fully deployed, ring 1807 isconstructed from a self-expanding or spring material, such as Nitinol,and is a shape-set sinusoidal patterned ring including a plurality ofcrowns or bends 1852 and a plurality of struts or straight segments 1854with each crown being formed between a pair of opposing struts. In anembodiment, the length of struts 1854 of ring 1807 ranges from the sameas the length of the struts on first end stent 1806A to 1/10 of thelength of the struts on first end stent 1806A. In an embodiment, thenumber of sinusoids of ring 1807 ranges from ⅓ the number of sinusoidsof first end stent 1806A to twenty times the number of sinusoids offirst end stent 1806A. Ring 1807 is thus from a material that can beprovided with a mechanical memory to return or recoil the ring from adelivery configuration in which interior sections 1830 transformattachment loops that extend beyond first edge 1802 of prosthesis 1800to an expanded deployed configuration in which the attachment loopsretract completely into tubular graft 1805. Although ring 1807 is shownwith alternating interior and exterior sections, it will be understoodby one of ordinary skill in the art that the ring may be coupled tofirst end stent 1806A via any configuration described herein, includingthose in which the ring does not pierce the graft material but ratherextends solely along the inside or outside surface of the graftmaterial.

In the above embodiments, the scaffolding or support of the stent-graftprostheses have been illustrated as a series of independent or separateself-expanding stents/sinusoidal patterned rings. However, as will beunderstood by one of ordinary skill in the art, the support structure orscaffolding of a stent-graft prosthesis may have other configurationssuch as a series of sinusoidal patterned rings coupled to each other toform a self-expanding stent. In another embodiment, the supportstructure or scaffolding of a stent-graft prosthesis may be a unitarytubular component such as but not limited to the configuration shown inFIG. 19. FIG. 19 illustrates a stent-graft prosthesis 1900 according toanother embodiment hereof in which the prosthesis includes a tubularradially-compressible stent or scaffold 1906 rather than a plurality ofstents formed as independent sinusoidal patterned rings. Stent-graftprosthesis 1900 is shown in its fully expanded or deployedconfiguration. Stent 1906 is coupled to a tubular graft 1905 to extendfrom a first proximal end 1902 to a second distal end 1904 thereof forsupporting the graft material and is operable to self-expand intoapposition with an interior wall of a body vessel (not shown). In theembodiment depicted in FIG. 19, stent 1906 is a unitary tubularcomponent having diamond-shaped openings 1956, which may be formed byvarious conventional stent forming methods as would be understood by oneof ordinary skill in the art. Stent 1906 includes endmost crowns 1908that are proximate to and inwardly spaced from first edge 1902 oftubular graft 1905. Each endmost crown 1908 is a curved segmentextending between opposing struts 1909 on stent 1906. Ring 1907 issimilar to ring 207 in that it passes through the graft material oftubular graft 1905 within each endmost crown 1908A of first end stent1906A such that ring 1907 includes alternating interior and exteriorsections 1930, 1932, respectively, which extend along inside and outsidesurfaces of tubular graft 1905, respectively. When coupled to a deliverysystem (not shown), interior sections 1930 that extend along the insidesurface of tubular graft 1905 are utilized to form attachment loops (notshown) that extend beyond first edge 1902 of prosthesis 1900. Althoughattachment ring 1907 is shown with alternating interior and exteriorsections, it will be understood by one of ordinary skill in the art thatthe ring may be coupled to stent 1906 via any configuration describedherein, including those in which the ring does not pierce the graftmaterial but rather extends solely along the inside or outside surfaceof the graft material.

While various embodiments according to the present invention have beendescribed above, it should be understood that they have been presentedby way of illustration and example only, and not limitation. It will beapparent to persons skilled in the relevant art that various changes inform and detail can be made therein without departing from the spiritand scope of the invention. Thus, the breadth and scope of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the appendedclaims and their equivalents. It will also be understood that eachfeature of each embodiment discussed herein, and of each reference citedherein, can be used in combination with the features of any otherembodiment. All patents and publications discussed herein areincorporated by reference herein in their entirety.

What is claimed is:
 1. A prosthesis for implantation within a bodylumen, the prosthesis being configured for delivery via a catheterhaving a tip capture mechanism at a distal end thereof, the tip capturemechanism including at least a first tip capture finger and a second tipcapture finger, the prosthesis comprising: a tubular graft of a graftmaterial; a stent coupled to the tubular graft and including a pluralityof crowns and a plurality of struts with each crown being formed betweena pair of opposing struts, the stent having endmost crowns that areadjacent to and distal of a proximal edge of the tubular graft, whereinthe endmost crowns are secured to the graft material of the tubulargraft; and a ring that directly engages the endmost crowns of the stent,wherein the ring includes a plurality of integral sections thatcollectively form the ring and each integral section extends between twoendmost crowns when the stent is in a compressed delivery configuration,and wherein each of a first integral section of the ring and a secondintegral section of the ring longitudinally extends beyond the proximaledge of the tubular graft as an attachment loop of the prosthesis thatis configured to engage the first tip capture finger and the second tipcapture finger, respectively, of the catheter when the stent is in thecompressed delivery configuration, the first and second integralsections being disposed at opposing locations of the stent, and whereineach of the first integral section of the ring and the second integralsection of the ring do not longitudinally extend beyond the proximaledge of the tubular graft when the stent is in an expanded deployedconfiguration.
 2. The prosthesis of claim 1, wherein the ring is acircular band when the stent is in the expanded deployed configuration.3. The prosthesis of claim 1, wherein the ring has a sinusoidalshape-set configuration when the stent is in the expanded deployedconfiguration.
 4. The prosthesis of claim 1, wherein each integralsection of the ring extends between a pair of adjacent endmost crowns.5. The prosthesis of claim 1, wherein the ring pierces the graftmaterial of the tubular graft and the plurality of integral sections ofthe ring alternate between inside and outside surfaces of the tubulargraft.
 6. The prosthesis of claim 1, wherein the stent is coupled to aninside surface of the tubular graft and wherein the ring directlyengages the endmost crowns without piercing the graft material of thetubular graft.
 7. The prosthesis of claim 1, wherein the stent iscoupled to an outside surface of the tubular graft and wherein the ringdirectly engages the endmost crowns without piercing the graft materialof the tubular graft.
 8. The prosthesis of claim 1, wherein all of theplurality of integral sections of the ring form attachment loops thatlongitudinally extend beyond the proximal edge of the tubular graft whenthe stent is in the compressed delivery configuration.
 9. The prosthesisof claim 1, wherein every other integral section of the ring formsattachment loops that longitudinally extend beyond the proximal edge ofthe tubular graft when the stent is in the compressed deliveryconfiguration.
 10. The prosthesis of claim 9, wherein the integralsections of the ring that do not form attachment loops are coupled tothe graft material of the tubular graft.
 11. The prosthesis of claim 1,further comprising: a plurality of stents coupled to a body of thetubular graft, wherein each stent is a sinusoidal patterned ring havinga first set of crowns near the proximal edge of the tubular graft and asecond set of crowns distant from the proximal edge of the tubular graftrelative to the first set of crowns.
 12. The prosthesis of claim 11,wherein the ring directly engages endmost crowns of a first stent mostproximate to the proximal edge of the tubular graft.
 13. The prosthesisof claim 12, further comprising: at least one suture extending between asecond stent adjacent to the first stent and an integral section of thering that does not form an attachment loop.
 14. The prosthesis of claim12, further comprising: a second ring coupled to struts of the firststent, wherein the second ring loops around the ring at at least oneintersection point on an integral section of the ring that does not forman attachment loop that longitudinally extends beyond the proximal edgeof the tubular graft.
 15. The prosthesis of claim 12, furthercomprising: a second ring coupled to a second stent adjacent to thefirst stent, wherein the second ring loops around the ring at at leastone intersection point on an integral section of the ring that does notform an attachment loop that longitudinally extends beyond the proximaledge of the tubular graft.
 16. The prosthesis of claim 11, wherein thering directly engages the first set of crowns of a second stent adjacentto a first stent most proximate to the proximal edge of the tubulargraft.
 17. The prosthesis of claim 1, wherein the stent is coupled tothe tubular graft to extend from the proximal edge of the tubular graftto a distal edge of the tubular graft.
 18. The prosthesis of claim 1,wherein the ring directly engages the endmost crowns of the stent bybeing woven between adjacent endmost crowns of the stent.
 19. A deliverysystem for implanting a stent-graft prosthesis within a body lumen, thedelivery system comprising: a catheter including an outer deliverysheath and a catheter shaft slidingly disposed within the outer deliverysheath, the catheter shaft having a tip capture mechanism at a distalend thereof, wherein the tip capture mechanism includes a first tipcapture finger and a second tip capture finger; and a stent-graftprosthesis mounted on the catheter shaft proximal to the tip capturemechanism at the distal end of the catheter shaft, the stent-graftprosthesis including a stent coupled to a tubular graft of a graftmaterial, wherein the stent includes a plurality of crowns and aplurality of struts with each crown being formed between a pair ofopposing struts, and endmost crowns that are adjacent to and distal of aproximal edge of the tubular graft and secured to the graft material ofthe tubular graft; wherein a ring directly engages the endmost crowns ofthe stent, a section of the ring being defined as the portion whichextends between two endmost crowns when the stent is in a compresseddelivery configuration, and wherein each of a first section of the ringand a second section of the ring longitudinally extends beyond theproximal edge of the tubular graft as an attachment loop of thestent-graft prosthesis that engages the first tip capture finger and thesecond tip capture finger, respectively, when the stent is in thecompressed delivery configuration, the first and second integralsections being disposed at opposing locations of the stent, and whereineach of the first section of the ring and the second section of the ringdo not longitudinally extend beyond the proximal edge of the tubulargraft when the stent is in an expanded deployed configuration.
 20. Aprosthesis for implantation within a body lumen, the prosthesis beingconfigured for delivery via a catheter having a tip capture mechanism ata distal end thereof, the tip capture mechanism including a first tipcapture finger and a second tip capture finger, the prosthesiscomprising: a tubular graft of a graft material; a stent coupled to thetubular graft and including a plurality of crowns and a plurality ofstruts with each crown being formed between a pair of opposing struts,the stent having endmost crowns that are adjacent to and distal of aproximal edge of the tubular graft, wherein the endmost crowns aresecured to the graft material of the tubular graft; and a ring thatdirectly engages the endmost crowns of the stent, a section of the ringbeing defined as the portion which extends between two endmost crownswhen the stent is in a compressed delivery configuration, wherein eachof a first section of the ring and a second section of the ringtransforms into an attachment loop of the prosthesis that longitudinallyextends beyond the proximal edge of the tubular graft and is configuredto engage the first tip capture finger and the second tip capturefinger, respectively, of the catheter when the stent is in thecompressed delivery configuration, the first and second integralsections being disposed at opposing locations of the stent, and whereineach of the first section of the ring and the second section of the ringretracts into the stent when the stent is in an expanded deployedconfiguration so that the ring has a diameter that is substantiallyequal to an expanded diameter of the stent.